Magnetic compass



c. W. EIsENII/IANN.

MAGNETIC COMPASS. APPLICATION FILED AUILIQ, I9I9.

Patented NOV. M, 1922.

2 SHEETS-SHEET l.

iiYllgllzlllll//l/l/l/l/lll C. W. EISENIVIANN.

v MAGNETIC COMPASS. APPLICATION FILED AUG.I9, i919. 1,485,633. l PatentedN0v.14,1922.

2 SHEETS-SHEET 2.

Patented Nov.. i4, i922.

CARL W. EISENIVIANN, OF NEBRASKA CITY, NEBRASKA.

yMAGrNIEi'lIC COMPASS.

Application led August 19, 1919. "Serial No. 318,530.

To allwwmz' may concern: '6 and a ring 7 engaging the same whereby Beit known that I, CARL EISENMANN, the compass may be attached to a chain or 55 a citizen of the United States, residing in Vconveniently held. A stall or pivot pin 8 Nebraska City, Nebraska, have invented projects axially in the casing from the botlMagneti@ Compasses7 of which the 'followtomQ thereof to which it is rigidly fixed and mg is a Specification a cup bearing 9 is rotatably mounted be- One Object of this invention is to S0 distweenvthe free pointed end of this pivot and 60 pose the movable or magnetic element ofa the Under Side of the glass cover. compass that it shall be possible to distin- In accordance with one form of my inven- 10 guish the position ot' the needle and more estion, the magnetic element or needle of the pecially its north end in a poor .light or 4COmpass is divided into two sections l0 and when the compass is at a distance aswell as 1l rigidl iiXed to the bearing 9 so as to pro- 65 when it is viewed at a relatively sharp angle ject in opposite directions therefrom but as is solnetmes necessary When the device is laterally CllSpllCeCl SO that ll IlOltll @11d l() 15 `used in making electrical tests. of said needle swings immediately under It is further desired to provide a` magvand adjacent the glass cover 3 while the netic compass in whichthe parts are so ar- South end ll which balances it, swings in a 70 rang-ed as t0 permit the position 0f the plane adjacent or below the central plane of `needle to be easily and quickly-determined the casing. The amount of the displacement even though it is oscillating as when first of the two parts ofthe magnet or needle 10 subjectedlto astrong magnetic fielder when and `11 or their arrangement is such as to Vthe compass as a whole is moving as is the permit ofthe extension between them of a 75 case when it is mounted uponfamotor vehicle diaphragm 4or partition 12 whereby the or used in air craft. south end of said needle is concealed from These objects and other advantageous observation.

ends l attain as hereinafterl set yforth, refer- In the case illustrated said diaphragm exence being had to the accompanying drawtends completely across the casing so as'to 80 ings, in which, divide it into two chambers, in the upper of Fig. l is a plan of a compass constructed which thenorth end 10 of the needle operin accordance with my invention; .ates while in the lower chamber is the south Fig. 2 is a transverse vertical section-on end 1l. The upper or exposed face of the the line 2-2, Fig. l; diaphragm l2 which is visible through the 85 Fig. 3 is a vertical section similar to Fig. glass covering is preferably marked with a 2, illustrating a slightly modified Jform of large and easily distinguishable N as inthe invention; dicated in Fig. l so that it is a simple mat- Fig. @L is a transverse vertical section, -ter to-distinguish the position of the north illustrating a double vfaced compass involvend of the needle even though it be in vio- 90 ing my invention; lent oscillation and viewed at an acute an- Fig. 5 isa plan of the second face of the Vgle to its plane of movement.

compass shown in Fig. 4, its first face'having In that form of the invention shown in the same appearance asthat ot the compass Fig.V 3 the diaphragm, as in the case or' Figs. shown in Fig. l; l and 2, is held in position between the two 95 Fig. 6 is a plan of another modiiication spacing rings 4 and 5 so as to conceal the of the invention; and south end of the needle and serve as a dial Fig. 7 is a transverse vertical section on for the north end thereof, although in this the line 7*?, Fig. 6. case the two parts l0 and ll of the needle are ln the above drawings l represents aflat rigidly fixed to a staff or spindle 13 so as to 10U cylindrical casing closed at one-end by an project in opposite directions therefrom integral bottom 2 and at the opposite end and said stall hasitsends formed to rotate with a glass cover 3. The latter rests upon in a suitable depression or cavity in the centhe upper of two spacing rings .tand 5 held ter of the glass cover 3 and in a hardened in place'by the inwardlyanged top edge of bearing 14 mounted at center of the bot- 105 the casing l, which is provided with an eye tom 2 of said casing respectively.

In that form of my .invention shown in Figs. land 5 l have provided a cylindrical metal casing 1fL having both of its ends inwardly flanged and respectively closed by two glass or other transparent covers 3 and 3u. Between these covers and holding them in place in the casing, are three spacing rings 16, 17 and 18 which also serve to position between them a pair of parallel diaphragms 19 and 20 which cooperate with each other and with the two covers 3 and 3 to form three chambers in the casing. A rotary staff or spindle 21 has its properly formed ends loperative in cavities in the centers of the two glass covers 3 and 3 and has rigidly fixed to it a two-part magnet needle 10-11 of which the north section 10 is visible through the cover 3 against the back ground provided by the diaphragm 20. The south end of this needle as before balances and projects oppositely from the north end 10 and is concealed in the intermediate chamber between the two diaphragms 19 and 20.

Also fixed to the staff 21 are two half needle sections 22 and 23 of non-magnetic material projecting in opposite directions therefrom and laterally displaced so that the first of them is operative within the intermediate chamber containing the south end of the magnetic needle while 'the second section 9.3, which is balanced by the half needle section 22, is operative in the chamber defined by the second glass cover 3a and the diaphragm 19 so that it is visible through said cover. This second diaphragm is preferably marked with a large letter E as indicated in Fig. 5 and it is to be noted that the two half needle sections 22 and 23 project from the staff in lines at right angles to the lines of the two-part magnet needle 10-11. As a consequence when the visible end 10 of the magnetic needle points to the north, the visible end Q3 of the non-magnetic needle points east so that with this form of the invention it is much more convenient to locate the east and west directions ythan with a compass pointing north and south only.

lf it be desired to reduce the axial length of the compass and simplify its construction, this may be done in the manner indicated in Figs. 6 and 7 by making its casing 1b relatively flat and mounting in it a single spacing ring 30 between the upper end of which and the inwardly fianged edge of the casing the glass cover 3 is mounted. As in that form of the invention shown in Fig. 17 the pivot pin 8 is fixed to and projects from the center of the casing bottom 2 and carries a cup bearing 9. ln this instance however' while the north end 10 of the magnetic needle which projects from this cup bearing has a length but little less than the radius of the casing, its south end is made in the form of a relatively short counter weight 31 projecting from said bearing in a line opposite that of the needle end 10 but so made as to be comparatively inconspicuous. ln this cz se the inner face of the bottom of the casing would be marked with a large N as indicated in Fig. 6 but, owing to its small size and the fact that it is preferably extended parallel with the pivot pin, the south end 31 is hardly noticeable, while as before the north end may be easily and quickly observed and its position noted. From the above description it will be seen that a compass constructed in accordance with my invention is particularly available for quickly indicating the directions even when the light is poor and' the conditions are such as would render an ordinary compass practically useless or at best difhcult to utilize for quick or angular observations.

I claim: j

1. The combination in a magnetic compass of a casing; a magnetic needle rotatably mounted therein and made in two axially displaced parts; with means for concealing one of said parts.

2. The combination in a magnetic compass of a casing; a magnetic needle rotatably mounted therein and made in two axially displaced parts; with means for concealing one of said parts consisting of a diaphragm mounted in the casing between the planes of movement of said needle parts.

3. The combination in a magnetic compass of a casing; a magnetic needle rotatably mounted therein; and a non-magnetic indicator movable with and projecting at right angles to the line of the needle; with means for concealing one half of each needle while permitting the remaining halves to remain visible.

ll. The combination in a magnetic compass of a casing having transparent covers at its opposite ends; a magnet rotatably mounted in the fasing and visible through one of the covers; with a non-magnetic indicator connected to and movable with the magnet and visible through the second cover.

5. lThe combination in a magnetic compass of a casing having transparent covers at its opposite ends; a magnet rotatably mounted in the casing and having a portion visible through one of the covers; a nonmagnetic indicator connected to and movable with the magnet and visible through the second cover; with means for concealing one pole of the magnet.

6. The combination in a magnetic compass of a supporting structure; and a magnet rotatably mounted in said structure7 having but a single indicating arm projecting on but one side of it-s axis of rotation and visible on one face of said structure; with a dial constituting a background for said indicating arm and having on it a letter indicative of the direction towards which the arin points.

i. The combination in a magnetic compass of a supporting structure; and a mag- 5 net rotatably mounted in said structure,

having but a single indicating arm proJecting on but one side of its axis of rotation and visible on one face of said structure; With a diaphragm concealing a portion of said magnet and having on it a letter indi- 10 catve of the direction toward Which the arm points.

In Witness whereof I ax my signature. CARL W. EISEN MANN 

